As illustrated in FIG. 21, JP2007-191025 (a conventional vehicle wheel disk) discloses a vehicle wheel disk including a hat portion 1 continuously extending in a circumferential direction of the disk and a plurality of circular vent windows 2 located outwardly of the hat portion 1 in a radial direction of the disk and arranged on a single circle.
The vehicle wheel disk of JP2007-191025 also has a disk portion 3 between adjacent vent windows 2.